Immersion molten metal sampler

ABSTRACT

An immersion-type molten material sampling unit comprised of a body of refractory material including an entrance passage, a first cavity for the production of a flat disclike sample, one or more additional cavities for the production of one or more pintype samples, and an air compression chamber vented to atmosphere which facilitates rapid filling of the sample cavities. The unit is mounted in one end of a protection tube to form a low-cost expendable assembly which may be readily slipped onto the end of a piece of pipe which serves as a handle for immersing the unit in a bath of molten material. In a preferred embodiment the first cavity desirably includes a pair of chill plates to produce more rapid freezing of the disclike sample and a pair of smoother surfaces which require less clean-up prior to use of the disc for spectrographic analysis.

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IMMERSION MOLTEN METAL SAMPLER CROSS-REFERENCES This is acontinuation-in-part of the parent application Ser. No. 850,961, filedAug. 18, 1969, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to apparatus for obtaining a sample of molten material. Suchapparatus is generally to be found in U.S. Patent Office classesrelating to Measuring and Testing, Sampler and Toller, Implements, WithReceptacle, Liquid, BIC.

2. Description of the Prior Art For over 30 years there has been acontinuing effort, particularly by individuals employed in the steelindustry, to pro vide a satisfactory method and apparatus for thecollection of solidified samples of molten material to be used forconstituent analysis. Samples have been obtained by pouring moltenmaterial into a mold having a cavity configuration of a desired shape.Pin-type samples have been obtained by immersing the closed end of ametal or heat-resistant glass suction tube into a bath of moltenmaterial so that upon destruction of the end closure molten materialwill be sucked up into the tube. Suction was achieved either byconnection to suction producing means or using a sealed evacuated tube.Other sampling apparatus disclosed in published material is comprised ofan immersible mold structure having a covered top, bottom, or sideentrance passage to a cavity of a desired shape, the mold structurebeing supported by a handle so that it could be immersed in a bath ofmolten material and the cavity filled by gravity or the hydraulic headof the molten material. In each of these latter modifications thecavities are vented to atmosphere.

Recent examples of the latter type of sampling apparatus are describedin papers published by R. Houston and F. Death, pages 4052, Proceedingsof Electric Furnace Conference, 1962; and D. A. Dukelow, H. F. Ramsteadand H. W. Meyer, pages 81-99, Proceedings of Open Hearth SteelConference 1962, Volume 45. Both are published by The MetallurgicalSociety of the American Institute of Mining, Metallurgical, andPetroleum Engineers. The foregoing papers each describe molten materialsamplers comprised of a capped tube supported at the immersion end of anelongated pipe employed as a handle. The tubes are vented to atmosphereand either contain an amount of deoxidizing material and/or are cappedwith a deoxidizing material such as aluminum. The tubes in both theHouston et al., and Dukelow et al., articles are of metal. The onedescribed by Dukelow et al., article is specifically referred to as asteel chill mold which is supported in the end of a cardboard tube.

An article by D. E. Grimes, A New Device for Sampling of Hot Metal atlnlands BOF Shop, Open Hearth Proceedings, A.I.M.E., 1968, pages 73-77,describes an immersion molten metal sampler comprised of a three-piececopper chill mold of a design to provide a pair of flat disclike metalsamples. This structure while functioning to produce samples of a typedesired is relatively speaking expensive and is not suitable for massproduction and further requires the reconditioning of parts thereof forreuse.

U.S. Pat. Nos. 3,369,406; 3,455,164; and 3,481,201 also disclosefeatures of construction utilized in various types of molten metalsamplers. For example, U.S. Pat. No. 3,455,l64G. P. Boyle, which isassigned to applicants assignee, discloses the use of shell molded sandsample mold halves supported in a cardboard tube, etc. U.S. Pat. No.3,48 l ,20lR. A. Falk, discloses use of a metal chill plate in anexpendable sampler.

While such prior art devices have been very useful, there have beenproblems resulting in failure each time to obtain a sound, satisfactorysample and/or the cost and inconvenience associated with the use thereofhas been burdensome.

More recently it has been found desirable to obtain both a pin-type"sample and a flat, square or disc sample of a bath of molten material tosatisfy the needs of various types of analysis equipment employed in asingle laboratory. For this reason samplers have evolved with moldshaving a cavity configuration simultaneously to provide both a flat andpin sample. In U.S. Pat. Nos. 3,415,124 and 3,415,125 there is disclosed immersion sampling equipment constructed and arrangedsimultaneously to provide both a pin and flat sample.

Prior art samplers have varied greatly as to their complexity, cost, andtheir ability each time to provide a satisfactory sample. Several of thesimplest, least expensive, and easiest to use devices have beenunsatisfactory since they sometimes produce incomplete, piped, or poroussamples and while applicant has employed many of the parts and forms ofconstruction disclosed in the references set forth above, he hasassociated the parts in a configuration not taught by nor believedobvious from the prior art to produce a low-cost expendable immersionsampler which produces superior results at minimum cost.

SUMMARY OF THE INVENTION In accordance with applicants invention thereis provided a dual sample unit and an assembly thereof simultaneously toobtain both a flat and a pin sample. The unit is characterized by itssimplicity of construction compared to known prior art dual units, itslow cost, and its features of construction which enhance the flow ofmolten material into the sample cavities in a manner to produce samplesfree of defects.

In accordance with applicants invention the sampling unit per se iscomprised of a body structure which is desirably a simple two-piece bodyof shell molded sand construction. The pieces are complementary andtogether form a body structure which includes an entrance passage oflimited length and restricted cross section at the immersion endthereof. The entrance passage opens into a large flat disclike cavitywhich provides a round flat sample portion. One or more tubular passageswhich are desirably lined with high-temperature glass tubing connect theflat sample cavity with an air compression chamber which is vented toatmosphere through a hollow manipulator structure. A tube of materialfor deoxidizing the molten sample is disposed in the entrance passage.Additionally, the entrance passage may be closed with a cap ofdeoxidizing material over which there is secured a protective cap whichprevents entry of molten material until the unit has passed throughforeign material and reached the molten material to be sampled. The tubeof deoxidizing material and the cap of deoxidizing material cooperate ina manner to deoxidize the material which initially flows into thesampler and continuously to deoxidize the sample as it is accepted bythe sampler until it is completely filled so that all of the sample isuniformly deoxidized. The sample unit is retained in the immersion endof a heavy walled cardboard tube which receives a pipe employed as ahandle for immersing the device into a bath of molten material and alightweight cardboard tube surrounds the immersion end in protectiverelation with the shell molded sand body to prevent damage theretoduring handling and shipment. All of the materials utilized in the samedevice are very low in cost thereby to make the entire structureeconomically expendable.

Further, in accordance with applicants invention, it has been foundpreferable to include in the flat disclike cavity a pair of chill platessecured to the flat surfaces thereof to aid in the production of flattersamples, prevent loss of metal at high superheat, prevent sampleporosity, minimize dendritic growth and when sampling iron alloysproduce a chilled sample structure thus to avoid the presence of freegraphite in the sample which would preclude the accurate analysis ofcarbon, phosphorous, and sulfur using a vacuum spectrometer.

Also, in accordance with a preferred form of applicants invention, thesample unit instead of being retained in the immersion end of the heavywalled cardboard tube which receives the pipe employed as a handle isretained within and by a short length of heavy cardboard in abuttingrelation with the tube which receives the handle. An end of the shortlength of tube which supports the sample unit surrounds and is cementedto an end of a smaller diameter cardboard tube which receives the pipeemployed as a handle. In use the short length of cardboard tube burnsthin and is easily knocked off and/or crushed for sample removal.

Further, in accordance with the preferred form of applicants invention,it has been found that under conditions of high superheat it isdesirable to further restrict the entrance passage by including thereina short length of glasslike material such as quartz tubing to aid theflow of sample into the unit and prevent partial drainage of sample fromthe unit.

It is an object of the invention to provide an expendable immersionsampler device of the type comprised of a mold body structure havingtherein one or more sample cavities to be filled by a sample of moltenmaterial characterized by an unobstructed air compression cavityconnected with a sample cavity and vented to atmosphere through arestricted passage.

It is also an object of the invention to provide an expendable immersionsampler of the type comprised of a split mold body structure havingtherein one or more sample cavities to be filled by a sample of moltenmaterial characterized by first and second mold halves each including acomplementary shallow cavity having a flat wall of substantial area, apair of metal chill plates, and means securing one of said pair of metalchill plates to said flat wall of each of said first and second moldhalves.

It is a further object of the invention to provide an expendableimmersion sampler of the type comprised of a mold body structure havingtherein one or more sample cavities to be filled by a sample of moltenmaterial characterized by a short cardboard tube supporting said moldbody structure, and a longer cardboard tube for supporting a handle,said short cardboard tube extending a sufficient length in surroundingrelation and affixed to said longer cardboard tube for supporting saidmold structure externally of said longer cardboard tube to facilitaterecovery of the sample of molten material by crushing said shortcardboard tube and its contents.

Additional objects and a better understanding of applicants inventionwill be had by a reading of applicants specification and the appendedclaims and referring to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is an elevation showing applicants invention assembled and readyfor immersion in a bath of molten material,

FIG. 2 is an elevation partly in section showing the interiorconstruction of applicants sampler,

FIG. 3 is an elevation partly in section of a slightly different form ofapplicants sampler, and

FIG. 4 is a side elevation partly in section taken along the lines 44 ofFIG. 3.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1, a samplereceiving shell mold 20 of sand having a cap 12 closing the entrancepassage of the mold is supported at the immersion end of a heavy walledcardboard tube 14. A relatively thin cardboard tube surrounds theportion of the sand body protruding from the cardboard tube 14 in orderto protect the relatively fragile sand mold during handling andshipment. This thin cardboard tube 15 extends in overlapping relationwith the cardboard tube 14. These assembled parts form a sampler 10.While specific materials such as a shell mold of sand and cardboard arepreferred it will be appreciated that other materials such as refractoryclay products, graphite, and metal parts covered with refractorysubstances and cements may be used. The materials described herein arepreferred because of their low cost, ready availability, and theknowledge that they are suitable for immersion in a bath of moltenmaterial such as molten steel. Additional information concerning thesematerials is clearly set forth in U.S. Pat. No. 3,455,164 and patentsreferred to therein.

The length of the tube 14 is not critical and will depend upon the typeof vessel containing the molten material which is to be sampled. When itis desired to obtain samples of molten steel from an open hearthfurnace, for example, a cardboard tube approximately 4 feet long may beused and into this may be inserted the end of an approximately 8-footlong piece of 4-inch extra heavy iron pipe 17 having an outside diameterwhich is a snug fit with respect to the inside diameter of the cardboardtube 14. A protuberance may be provided on the pipe to assure a snugfit. Such a protuberance is shown in FIG. 5 of the above-mentioned U.S.Pat. No. 3,455,l64. A metal ring 18 is desirably welded at a distance ofabout 3 feet from the immersion end of the pipe 17 thus to provide astop for the cardboard tube 14 so that the pipe 17 projects into thecardboard tube 14 for a distance of about 3 feet which provides ampleclearance between the end of the pipe which functions as a handle ormanipulator and the mold 20 in the immersion end of the cardboard tube.

In prior immersion sampling devices it has been a problem each time tosecure a satisfactory sample, that is to say, with many prior devicessatisfactory samples are obtained only 70 to percent of the time.Imperfect or unsatisfactory samples are characterized by a lack ofcomplete filling of a sample cavity and/or undesirable porosity of thesample. Applicants have discovered that in addition to providingsufficient material for deoxidizing a sample as taught in the prior arta further improvement in sampler performance can be obtained byproviding a free, unobstructed space to serve as an air compressionchamber within the mold thus to promote rapid and complete filling ofthe sample cavities. With this improvement satisfactory samples areobtained almost every time a sample is taken.

In accordance with the foregoing, as more clearly shown in FIG. 2, thesample mold 20 of FIG. 1 is comprised of a pair of symmetrical halves11. Each half 11 includes grooves and recesses described hereinafterwhich together form an entrance passage, a first sample cavity, one ormore additional sample cavities, an air compression chamber, andpassages venting the air compression chamber to atmosphere. Thereference numbers hereinafter applied to the grooves and recesses maylikewise be considered as applying to the passages and cavities theyform when the parts of the mold are assembled. The entrance passage ofrestricted cross section and relatively short length is formed bygrooves 11b in each mold half. The first sample cavity is formed bydepressions 11a in each mold half. An additional sample cavity or, asshown, additional sample cavities are formed by one or more grooves ineach mold half. An air compression chamber is formed by mating recesseslle. This feature not found in the prior art promotes rapid and completefilling of the sample cavities in avoidance of piping and porosity. Oneor more vents to atmosphere are formed by one or more small grooves 11fin each of the mating halves. These grooves being quite narrow cooperatewith the porosity of the sand body as described in U.S. Pat. No.3,455,164 to release air but are nevertheless small enough quickly tofreeze molten material so that it will not flow on into the cardboardtube 14.

One mold half desirably has a plurality of recesses or depressions suchas 11d which mate with correspondingly shaped protrusions in the matingmold half thereby properly to align the mold halves when they are placedtogether. At the mouth of the entrance passage 1 1b there is desirablyincluded a tube 19 of deoxidizing material such as aluminum. As pointedout in the above-mentioned paper by Houston and Death, tubes 16 of arefractory material having a smooth surface such as high-temperatureglass, fused silica or the like in grooves 110 aid the flow of themolten material and produce pins which are smooth and of uniformdiameter. With items 16 and 19 in place the mold halves are spread witha thin coat of cement and placed in abutting sealed relation. It hasbeen found desirable, however, prior to cementing the molded halvestogether to cover the walls of the cavity portion 110 with a refractorycement thus to seal the porous sand surface.

After the two halves have been secured together an aluminum cap 13 isslid over the immersion end of the mold thus to supply additionaldeoxidizing material at the entrance to passage 11b. Deoxidation of thematerial of the sample is commonly referred to in the art as killing"the sample. The aluminum cap "kills the steel in the immediate vicinityof the entrance passage. This steel is the first to enter the cavity.The

aluminum tube 19 is fixed by refractory cement in the entrance passageso that the steel must pass through the aluminum tube. The tube 19 isreacted with the steel from its inner wall toward its outer wall,killing also the last portion of steel to enter the cavity. A cover 12which may be in the form of a thin steel cap is cemented in place overthe aluminum cap 13. This cap will withstand a higher temperature thusto prevent molten material from reaching the entrance to the sampleruntil after the sampler has been immersed below the slag level. Thecement is indicated in FIG. 1 by the dotted line bearing the referencenumeral 21.

Since the shell molded sand is of a relatively soft and crumbly materialit has been found desirable to protect it with a thin cardboard tubewhich completely covers the exposed portion of the mold and extends inoverlapping relation with the cardboard tube 14 into which the samplemold is inserted for use. The use of cardboard tubes in expendableimmersion temperature measurements is well known to those skilled in theart. The expendable immersion techniques being described in U.S. Pat.Nos. 2,999,121 and 3,038,951 issued to H. G. Mead.

In use the immersion sampler 10 is slid onto the immersion end of thepipe 17 of FIG. 1 and into abutting relation with the ring 18. Thesample is immersed into a bath of molten material for a period of a fewseconds during which time the molten material fills the sample cavities.The material will solidify in the entrance passage 11b thus to retainthe molten material in the sample cavities while the device iswithdrawn. After withdrawal the mold is immersed in cold water to speedthe solidification process after which the thin cardboard tube 15 havingbeen consumed permits removal of the mold from the cardboard tube 14.After removal of the mold the mold is easily fractured and thesolidified sample retrieved. Excess material is removed and the pins cutapart for analysis.

In FIGS. 3 and 4 there is shown a modification of applicants immersionsampler 10 which has been designated by the reference numeral 30. Inthese two figures the same reference numerals are used for those partswhich are identical to the parts shown in FIGS. 1 and 2. Parts whichcorrespond in function to those shown in FIGS. 1 and 2 but differ intheir configuration are given the same reference numeral with a primeadded. New parts have been given new reference numerals.

The symmetrical halves 11' of FIG. 3 differ slightly from those shown inFIGS. 1 and 2 in that the portions of each mold half 11' containing thegrooves 11c, and part of the length of mating recesses lle, extend themaximum width of the mold halves which together form a diameter which isa slide fit into a cardboard tube 15 which is somewhat thicker than thecardboard tube 15. The end portions of the symmetrical halves 11,adjacent the grooves 11f, have a width less than maximum together toproduce an end on the sample mold of somewhat smaller diameter making iteasier to insert the sample mold into the short tube 15. It may beobserved in FIG. 3 that the end of the sample mold abuts the end of thelonger cardboard tube 14 instead of being supported therein. Thisconstruction facilitates recovery of the sample. In use after thesampler is withdrawn from the bath of molten material, the cardboardtube 15' will have disintegrated by an amount sufficient such that it iseasily broken away from the protected portion of cardboard tube 14 sothat the cardboard tube 15 may be crushed and the sample easily removedtherefrom. In the modification of FIGS. 3 and 4 the tubes 14 and 15 arecemented or otherwise fastened together.

The recesses and depressions 11d which mate with corresponding shapedrecesses and protrusions in the mating mold half in the device of FIGS.3 and 4 are elongated and have rounded surfaces thus to provide foreasier alignment of the mold halves.

As best shown in FIG. 4 each of the circular cavities 11a of the moldhalves 11' is relatively shallow and of substantial area and has securedtherein as by a refractory cement a flat metal disc 24 which may be, forexample, an approximately 1% inches diameter cold rolled steel discapproximately oneeighth of an inch thick. These discs serve as chillplates quickly to freeze the molten metal as it flows into the cavity 1la. It has been found that over a wide range of molten metaltemperatures varying from little or no superheat to substantialsuperheat of the molten metal better disclike samples are obtained inthat on the average they are flatter and require less cleanup for use ina vacuum spectrometer. Additionally, the chill plates serve to preventloss of metal at high superheat, prevent sample porosity, and minimizethe dendritic growth in the sample. Additionally, if the sampler be usedfor sampling iron alloys, the chill plates produce a chilled samplestructure thus to avoid the presence of free graphite in the samplewhich would preclude the accurate analysis of carbon, phosphorous, andsulphur when using a vacuum spectrometer.

By the addition of a fused quartz tube or other glasslike materialresistant to the temperature of the molten material in the entrancepassage 11b further to restrict the internal diameter of the entrancepassage, it is found that particularly under conditions of highsuperheat partial drainage of sample from the unit is minimized.

Under some conditions it may be found desirable to employ two steelcaps, particularly when using applicants sampler in a basic open-hearthfurnace to provide added protection during the time the sampler istraversing the distance through the furnace prior to immersion in themolten material contained in the furnace. When this is done the cap 12'will have a configuration such that a second steel cap 25 may be placedthereunder.

Immersion samplers of the types disclosed in FIGS. 1-4 may be comprisedof two molded halves 11 or 11 about 5% to 6 inches long having anoutside diameter of approximately 1% inches. The tubes 16 may be made ofhigh-temperature glass such as Vycor or fused quartz 2 inches longhaving an outside diameter of approximately nine thirty-seconds of aninch and an inside diameter of about one-fourth inch. The sleeve 19 ofdeoxidizing material may be a piece of aluminum tubing aboutthree-fourths of an inch long, have an outside diameter aboutfive-sixteenths of an inch, and an inside diameter of about ninethirty-seconds of an inch. In the modification shown in FIGS. 3 and 4the tube 23 may desirably be of high-temperature glass or fused quartzhaving an outside diameter of about nine thirty-seconds of an inch andan internal diameter of about thirteen sixty-fourths of an inch. Thecircular sample cavity 11a in each mold half may be about threeeighthsof an inch deep.

While the invention has been described in terms of preferred embodimentsand some specific dimensions have been set forth as illustrative, thematerial set forth should not be considered limiting, inasmuch as theprinciples underlying the invention will suggest to those skilled in theart many modifications which come within the scope of the claims.

What is claimed is:

1. An expendable immersion sampler device comprising a tube of materialcapable of withstanding immersion in a molten bath for a time sufficientto permit obtaining a sample,

a mold of refractory material supported by the immersion end of saidtube,

said mold having a pair of symmetrical halves each including grooves andrecesses which together form a plurality of serially connected passagesand sample cavities including an entrance passage formed by grooves, afirst sample cavity formed by recesses of a shape and depth to produce aflat" sample, one or more additional sample cavities formed by grooveshaving a shape to produce a pin sample, an air compression chamberformed by recesses, and grooves forming a vent for venting said aircompression chamber to atmosphere,

a closure member of deoxidizing material at the entrance of saidentrance passage, and

a tubular member of deoxidizing material in said entrance passage, saidmembers of deoxidizing material cooperating in a manner to kill saidsample in the vicinity of the entrance passage prior to flow thereofinto said sampler and thereafter continuously to kill said sample as itflows through said tubular member including the last portion of saidsample entering said sampler.

2. An expendable immersion sampler device according to claim 1 wherein achill plate is supported in the recess of each mold half which recessestogether form said first sample cavity.

3. An expendable immersion sampler device according to claim 1 whereinsaid tube of material is a first cardboard tube having a wall thicknesswhich is thinner and a length which is shorter than a second cardboardtube which supports the first cardboard tube with respect to a handlethus to facilitate recovery of a sample of molten material by crushingsaid first cardboard tube and its contents.

1. An expendable immersion sampler device comprising a tube of materialcapable of withstanding immersion in a molten bath for a time sufficientto permit obtaining a sample, a mold of refractory material supported bythe immersion end of said tube, said mold having a pair of symmetricalhalves each including grooves and recesses which together form aplurality of serially connected passages and sample cavities includingan entrance passage formed by grooves, a first sample cavity formed byrecesses of a shape and depth to produce a ''''flat'''' sample, one ormore additional sample cavities formed by grooves having a shape toproduce a ''''pin'''' sample, an air compression chamber formed byrecesses, and grooves forming a vent for venting said air compressionchamber to atmosphere, a closure member of deoxidizing material at theentrance of said entrance passage, and a tubular member of deoxidizingmaterial in said entrance passage, said members of deoxidizing materialcooperating in a manner to kill said sample in the vicinity of theentrance passage prior to flow thereof into said sampler and thereaftercontinuously to kill said sample as it flows through said tubular memberincluding the last portion of said sample entering said sampler.
 2. Anexpendable immersion sampler device according to claim 1 wherein a chillplate is supported in the recess of each mold half which recessestogether form said first sample cavity.
 3. An expendable immersionsampler device according to claim 1 wherein said tube of material is afirst cardboard tube having a wall thickness which is thinner and alength which is shorter than a second cardboard tube which supports thefirst cardboard tube with respect to a handle thus to facilitaterecovery of a sample of molten material by crushing said first cardboardtube and its contents.